Furnace control



Oct. 21, 1941.

w. E. FIREHAMMER 2,259,973

FURNACE CONTROL Filed Oct. 9, 1959 2 Sheets-Sheet 1 I InvEntmP WE.F'xrahammer Httmrnega Oct. 21, 1941.

w. E. FIREHAMMER 2,259,973

FURNACE CONTROL Filed 001;. 9, 1939 2 Sheets-Sheet 2 In /E 11;:11 W.E.FTHE-hammer Flt'tnrnega Patented Oct. 21, 1941 UNITED STATES PATENTOFFICE FURNACE CONTROL Welton E. Firehammer, Oshkosh, Wis.

Application October 9, 1939, Serial No. 298,679

2 Claims.

This invention appertains to furnace controls, and is an improvementover my application for Control devices for heating systems, Serial No.203,092, filed April 20, 1938, and matured into Patent No. 2,179,120,dated November 7, 1939.

One of the primary objects of my present invention is to provide meanswhereby the solenoid-actuated operating lever for the swinging dampergate is free of the damper gate, except by contact, thereby allowing thedamper gate to be under the direct influence of the chimney temperaturesor any atmospheric pressures when the said operating lever is drawn backby virtue of the operation of the solenoid magnet plunger attached tothe lever.

Another salient object of my invention is to provide an operating leverhaving an anti-friction roller for rolling contact with an inclinedtrack carried by and mounted upon the outer face of the damper gate topermit the damper gate to open to a greater degree with a progressivelyaccelerated motion without changing the length of the lever travel.

Another important object of my invention is to provide a novel fixturefor supporting and locating the adjustable damper gate weights, wherebythe weights are independent of one another and adjustable for anydesired draft value, the operation of the weights permitting the dampergate to become progressively lighter in weight as it opens in itsmaximum open range, thereby accommodating the power input of thesolenoid to' the point where less spring tension is required to completethe operation cycle.

A still further object of my invention is the provision of a noveldesign and method of controlling the cross-sectional area of anysmokepipe or breaching with the use of an atmospherically controlledinternal damper gate in direct combination with an externally mountedmotorized, atmospherically operated damper gate. A still furtherimportant object of my invention is to provide novel means for mountingthe internal gate in the smoke-pipe on one side of the furnace ofbreach-pipe, whereby to insure the proper and accurate operation thereofat all times.

With these and other objects in view, the invention consists in thenovel construction, arrangement, and formation of parts, as will behereinafter more specifically described, claimed,

and illustrated in the accompanying drawings,

. in which drawings:

pipe connecting a heating plant with a stack or chimney, with my novelappliance incorporated therewith, parts of the view being shown brokenaway and in section to illustrate structural detail.

Figure 2 is a vertical, sectional view taken on the'line 2-2 of Figure1, looking in the direction of the arrows, illustrating the externaldamper and the operating mechanism therefor.

Figure 3 is an enlarged, detail, horizontal, sectional view taken on theline 3-3 of Figure 1, looking in the direction of the arrows,illustrating the mounting of the electro-magnet in its supportingcasing.

-Figure 4 is a detail, vertical, sectional view taken on the line 4-4 ofFigure 1, looking in the direction of the arrows, illustrating theinternal damper.

Figure 5 is an enlarged, detail, diagrammatic view illustrating one formof means for delaying the action of the external damper gate.

Referring to the drawings in detail, wherein similar referencecharacters designate corresponding parts throughout the several views,the numeral Iil indicates a smoke-pipe leading to a stack or chimney H.A breach-pipe 12 connects an intermediate part of the smoke-pipe withthe heating plant M. This leaves a part of the smoke-pipe l0 projectinglaterally beyond the furnace or breach-pipe l2. The heating plant H canbe of any desired character and can be Stoker-fed or oil-fired. Inaccordance with my invention, I arrange an external damper 15 for thesmoke-pipe and an internal damper 5| for the smoke-pipe. These dampersl5 and 5| are disposed on opposite sides of the breach-pipe l2, and thearrangement and operation of the dampers relative to one another and tothe stackand furnace forms an essential part of my present invention.Each damper will now be described in detail.

The external damper 15 includes an annular damper ring or frame I6,which is securely fastened, as at H, to the outer end of the smokepipeID. The extreme lower end of the ring or frame has formed thereon adepending foot I8, to which is fastened the bracket IQ for supportingthe various operating parts of, the damper and the casing 20 for saidoperating parts.

Rockably mounted within the ring or frame I5 is the damper gate or plateii. The gate can be formed from sheet metal, if so desired, and theperiphery thereof is inturned to provide a reinforcing flange 22. Thegate, at a point above its horizontal diametric center, has securedthere- From the construction so far, it can be seen that the bottom ofthe damper gate overbalances the upper end'of the damper gate, and,hence,

the damper gate normally tends to swing to a closed position. However,in order to accurately balance and set the damper gate to suit variousdrafts, atmospheric pressures, etc., at diflerent stacks and pipes, thegate has adjustably associated therewith, above its horizontal center,certain weights, which will now be described in detail.

Disposed at the vertical center of the damper gate is aweight-supporting rod 25, and the ends of the rod are adjustably securedin blocks 26 firmly bolted to the damper gate. Slidably mounted upon therod .25 is a weight 21, and this weight is held in its adjusted positionby a set screw 28, which can be moved into and out of contact with therod. By this construction and arrangement, the weight 21 can be movedtoward and away from the horizontal center of the damper gate.

Adjustable on the rod 25 betwee'nthe shaft 23 and the weight 21 is ablock 23, and this block is held in an adjusted position by a set screw30. Extending outwardly from the block 23 is a threaded rod 3|, on whichis threaded the weight 32. The weight can be held in'an adjustedposition on the threaded rod by lock nuts 33. By this construction andarrangement, the weight 32 can be moved toward or away from the innerface of the damper gate.

In order to limit the outward swinging of the lower end of the dampergate, a resilient cushion 34 can be secured to the bracket l9andarranged in the path of the lower end of said gate.

having a movable plunger 36. The solenoid is slidably mounted on a track31 carried by the the damper gate to a closed position, and thedampercan actuate automatically under the infiuence of stack drafts,atmospheric pressure, etc. Rearward swinging movement of the operatinglever can be limited by the use of an adjustable rod 49, which ismounted in a slide block 50. This rod'49 can be moved back and forthtoward the lever to the desired and correct position.

While 'I have not shown the solenoid in the motor-circuit of a coalstoker or in the motor circuit of an oil burner, it is to be understood.

feed of coal or oil is closed, the solenoid is energized, and the dampergate will have a tendency to move to its closed position. Thus, when adepending arm 33 of the bracket l9. Set screws 4 33 adjustablyassociated with the depending arm 38 engagethe opposite ends of thesolenoid and adjustably clamp and hold the solenoid in the correctdesired place. An operating lever 40 of the bell-crank order is alsorockably mounted on the bracket l9, and the same includes an upperarcuate long' arm 4| extending toward the damper gate. The extreme upperend of the arm 4| carries an anti-friction roller 42 for rolling contactwith an inclined track 43 rigidly secured.

to the outer face of the damper gate. The hub Y of the lever 40 is.provided with an arcuate face 44, which constitutes the short arm of"the lever,

and thisarcuate face has secured thereto a flexible pull cable 45. Thelower end of the pull cable is firmly attached to the plunger 33 of thesolenoid 35. Rigidly securedto the rock shaft 46 of the operating leverfor swinging movement with the rock shaft and lever are outwardlyextending rods 41, and these rods 41 are connected to the bracket I! bycontractile coil springs 48.

The springs 43 normally tend to rock the lever and swing the inner upperend thereof into engagement with the track 43 for rocking .the gate onits pivot against the action of. gravity on the weights. Obviously, whenthe solenoid. 35 is energized, the. lever is pulled away fromtherlamper' gate, and, hence, the weights are free to move 7 5'-solenoid plunger 36. By providing the roller 42, a minimum amount ofresistance to the force of the springs 43 is set.

The inclined roller track 43 attached to the damper gate permits thedamper gate to open to a greater degree with a progressively acceleratedmotion without changing the length of the lever travel. This permits theuse of a relatively short lever on the operating end, and a longer leveras exists on the plane of the damper gate in respect to thecenter-to-center distance of the lever roller and the axis of the dampergate. By having the rods 41 adjustable on the rock shaft '46, I.havedevised a novel method for setting and controlling the spring tensionrequired to open the damper gate at the time the solenoid magnet isdeenergized.

As the bracket l9'efiectively supports and carries the imperforatecasing 20,the solenoid and plunger is protected against moisture andother corrosive elements, and, if desired, an oil dashpot can beemployed to enclose the magnet in an Y oil bath.

As the weights 21 and 32 are independent of one another, the weights canbe readily adjusted and set for any desired draft value, and theoperation of the weights permits the damper gate to become progressivelylighter in weight as it opens in its maximum open range. Now, referringtothe inner damper 5|, the

same includes a'disc-shaped damper plate or gate 52. This gate- 52 hasfirmly secured thereto, above its shaft 53. This rock shaft, at itspoint of contact with the gate 52, can be of a square shape inspecifically set forth. It is to be noted, however, that one end of theshaft 53 'is extended beyond the bearing bracket on one side, as at55,for a purpose which also will be more fully explained.

The bearing brackets. 54 are .mounted upon plates 56, and the edgesof'the plates carry bearing pintlw 5.1, which are rotatably received inbearing ears 58 formed og'attaching plates 53.

horizontal diametric center, a rock Set screws 60 are carried by thebearing ears for engaging the bearing pins, whereby to adjustably holdthe plates 56 in the desired set position. The inner faces of thebearing plates 59 are notched, and the bearing ears 58 are rounded forengagement with the pipe, and the opposite ends of the bearing platesreceive adjustable securing bolts 6|. The bolts, on opposite sides ofthe plates, can be adjusted in and out, so as to secure the properalinement of the. bearing brackets 54. v

The extended end 55 of the shaft 53 has ad- Justably mounted thereon asupporting block 62. This block has radially extending therefrom atquarters, threaded rods 83 and 64. when the gate is in its closedposition, the rod 63 is in a substantially horizontal position, whilethe rod 64 is in a substantially vertical position. The rod 53 hasthreaded thereon a weight 65, while the rod 54 has threaded thereon aweight 58. These weights 65 and 66 are adjustable on their respectiverods toward and away from the supporting block 82. By this arrangementof parts, the accurate balancing and setting of the gate to stack draftscan be accomplished.

The lower end of the smoke-pipe I is slotted, as at 51, for thereception of a depending finger 58, which is secured to the lower end ofthe damper gate. This finger cooperates with means for lessening theshock of the closing of. the gate, and the means for cooperating withthe finger includes a cylinder is firmlybolted to the smoke-pipe. Thecylinder 69 has slidably mounted therein a plunger" and a plunger rod1|. Springmeans I! normally urges theplunger and plunger rod outwardly,with the plunger rod toward the finger. The opposite ends of thecylinder have formed therein air escape ports, the size of which can beaccurately controlled by set screws I3. I lay considerable stress on themeans of mounting the internal damper gate, as the bearing brackets canbe accurately disposed and brought into proper alinement for receivingthe supporting shafts By my arrangement of internal and externaldampers, I--have designed and developed a novel to exert itself on thegreater lower half area of the internal damper gate, which seeks toclose it against the. action of the counterweights. This reduces thedraft ffect over the fire.

when the external damper gateis in its open position, the internaldamper gate is in its closed Where'anoil burner is utilized, it is riotdesirable to check the draft too rapidly. In Figure 5, I haveillustrated a means for delaying the opening of the external gate. Adelay of from one to five minutes can be provided, according to theadjustment of the device.

As shown in Figure 5, the plunger 36 of the solenoid carries a laterallyextending rod 31', which is adapted to strike a rod 14 of a plunger I5mounted in a closed cylinder l6. Thiscylinder 15 has formedtherein anair escape port 11, and the size of this port is adjusted by a screw 18.By varying the size of the port I1, the time of the delay of thechecking of the draft can be controlled. Upon the deenergizing of themagnet 35, the operating lever 40 and the damper gate tends to rock, andthe damper gate tends to swing to an open position. Rocking movement ofthe lever 40 under the influence of its springs is checked by themovement of the plunger 15 I acting against the trapped air in thecylinder 16.

Various changes in details may be made with- 'out departing from thespirit of the scope of my invention, but what I claim as new is:

1. In a furnace control, a smoke-pipe, an annular frame in thesmoke-pipe, a damper gate, means rockably supporting the damper gate inthe frame above its horizontal diametric center,

method of controlling the cross-sectional area of any smoke-pipe orbleaching with the use of an atmospherically controlled internal dampergate in direct combination with an externally mounted, motorized,atmospherically operated damper gate. This means that as the vacuumpressure of the bleaching varies with the motion of the external dampergate II, the internal damper gate 52 is forced to accept either an. openor closed position, as the case may be, or any point. of its normaltravel arc. It further means that the weights on the internal dampergate are set to'hold the gate in anopen position against the pull of thestack draft, and the weights of the external damper gate are set to openwith the pull of the stack.

As the draft increases, the external damper will open, Lpermitting fullatmospheric pressure engaged by the roller. I

a bracket secured to the frame, an operating lever having-a long arm anda short arm rockably mounted upon the bracket, a solenoid including aplunger connected to the lever, means operatively connecting the plungerto the short arm of the lever,. an anti-friction roller on the outer endof the long arm of the lever, and an inclined track on the damper gate2., In a furnace control, a smoke-pipe, a damper gate rockably mountedabove its horizontal di-' ametric center in said smoke-pipe, weightsnormally tending-to move the gate to a closed position, a movable leverengaging the gate belew its pivot, spring means acting on the lever formoving the lever against the gate to open the same, means for actuatingthe lever against the tension of said spring means, and means fordehyinl the return movement of the lever with the tension of said springmeans after actuation of the lever.

WELTON E. I 1' Urumadapted to be

